fix: Fixed all findings from the architecture tests

src/Nager.Date/HolidayProviders/AlandHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Åland HolidayProvider
     /// </summary>
-    internal class AlandHolidayProvider : IHolidayProvider
+    internal sealed class AlandHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/AlbaniaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Albania HolidayProvider
     /// </summary>
-    internal class AlbaniaHolidayProvider : IHolidayProvider
+    internal sealed class AlbaniaHolidayProvider : IHolidayProvider
     {
         private readonly IOrthodoxProvider _orthodoxProvider;
         private readonly ICatholicProvider _catholicProvider;

src/Nager.Date/HolidayProviders/AndorraHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Andorra HolidayProvider
     /// </summary>
-    internal class AndorraHolidayProvider : IHolidayProvider
+    internal sealed class AndorraHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/ArgentinaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Argentina HolidayProvider
     /// </summary>
-    internal class ArgentinaHolidayProvider : IHolidayProvider
+    internal sealed class ArgentinaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/AustraliaHolidayProvider.cs

@@ -11,7 +11,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Australia HolidayProvider
     /// </summary>
-    internal class AustraliaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class AustraliaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/AustriaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Austria HolidayProvider
     /// </summary>
-    internal class AustriaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class AustriaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BahamasHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Bahamas HolidayProvider
     /// </summary>
-    internal class BahamasHolidayProvider : IHolidayProvider
+    internal sealed class BahamasHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BarbadosHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Barbados HolidayProvider
     /// </summary>
-    internal class BarbadosHolidayProvider : IHolidayProvider
+    internal sealed class BarbadosHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BelarusHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Belarus HolidayProvider
     /// </summary>
-    internal class BelarusHolidayProvider : IHolidayProvider
+    internal sealed class BelarusHolidayProvider : IHolidayProvider
     {
         private readonly IOrthodoxProvider _orthodoxProvider;
 

src/Nager.Date/HolidayProviders/BelgiumHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Belgium HolidayProvider
     /// </summary>
-    internal class BelgiumHolidayProvider : IHolidayProvider
+    internal sealed class BelgiumHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BelizeHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Belize HolidayProvider
     /// </summary>
-    internal class BelizeHolidayProvider : IHolidayProvider
+    internal sealed class BelizeHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BeninHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Benin HolidayProvider
     /// </summary>
-    internal class BeninHolidayProvider : IHolidayProvider
+    internal sealed class BeninHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BoliviaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Bolivia HolidayProvider
     /// </summary>
-    internal class BoliviaHolidayProvider : IHolidayProvider
+    internal sealed class BoliviaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BosniaAndHerzegovinaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Bosnia and Herzegovina HolidayProvider
     /// </summary>
-    internal class BosniaAndHerzegovinaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class BosniaAndHerzegovinaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly IOrthodoxProvider _orthodoxProvider;
 

src/Nager.Date/HolidayProviders/BotswanaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Botswana HolidayProvider
     /// </summary>
-    internal class BotswanaHolidayProvider : IHolidayProvider
+    internal sealed class BotswanaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BrazilHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Brazil HolidayProvider
     /// </summary>
-    internal class BrazilHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class BrazilHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/BulgariaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Bulgaria HolidayProvider
     /// </summary>
-    internal class BulgariaHolidayProvider : IHolidayProvider
+    internal sealed class BulgariaHolidayProvider : IHolidayProvider
     {
         private readonly IOrthodoxProvider _orthodoxProvider;
 

src/Nager.Date/HolidayProviders/CanadaHolidayProvider.cs

@@ -11,7 +11,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Canada HolidayProvider
     /// </summary>
-    internal class CanadaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class CanadaHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/ChileHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Chile HolidayProvider
     /// </summary>
-    internal class ChileHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class ChileHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/ChinaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// China HolidayProvider
     /// </summary>
-    internal class ChinaHolidayProvider : IHolidayProvider
+    internal sealed class ChinaHolidayProvider : IHolidayProvider
     {
         /// <summary>
         /// China HolidayProvider

src/Nager.Date/HolidayProviders/ColombiaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Colombia HolidayProvider
     /// </summary>
-    internal class ColombiaHolidayProvider : IHolidayProvider
+    internal sealed class ColombiaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/CostaRicaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Costa Rica HolidayProvider
     /// </summary>
-    internal class CostaRicaHolidayProvider : IHolidayProvider
+    internal sealed class CostaRicaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/CroatiaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Croatia HolidayProvider
     /// </summary>
-    internal class CroatiaHolidayProvider : IHolidayProvider
+    internal sealed class CroatiaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/CubaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Cuba HolidayProvider
     /// </summary>
-    internal class CubaHolidayProvider : IHolidayProvider
+    internal sealed class CubaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/CyprusHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Cyprus HolidayProvider
     /// </summary>
-    internal class CyprusHolidayProvider : IHolidayProvider
+    internal sealed class CyprusHolidayProvider : IHolidayProvider
     {
         private readonly IOrthodoxProvider _orthodoxProvider;
 

src/Nager.Date/HolidayProviders/CzechRepublicHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Czech Republic HolidayProvider
     /// </summary>
-    internal class CzechRepublicHolidayProvider : IHolidayProvider
+    internal sealed class CzechRepublicHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/DenmarkHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Denmark HolidayProvider
     /// </summary>
-    internal class DenmarkHolidayProvider : IHolidayProvider
+    internal sealed class DenmarkHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/DominicanRepublicHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Dominican Republic HolidayProvider
     /// </summary>
-    internal class DominicanRepublicHolidayProvider : IHolidayProvider
+    internal sealed class DominicanRepublicHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/EcuadorHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Ecuador HolidayProvider
     /// </summary>
-    internal class EcuadorHolidayProvider : IHolidayProvider
+    internal sealed class EcuadorHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/EgyptHolidayProvider.cs

@@ -8,7 +8,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Egypt HolidayProvider
     /// </summary>
-    internal class EgyptHolidayProvider : IHolidayProvider
+    internal sealed class EgyptHolidayProvider : IHolidayProvider
     {
         /// <inheritdoc/>
         public IEnumerable<Holiday> GetHolidays(int year)

src/Nager.Date/HolidayProviders/ElSalvadorHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// El Salvador HolidayProvider
     /// </summary>
-    internal class ElSalvadorHolidayProvider : IHolidayProvider
+    internal sealed class ElSalvadorHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/EstoniaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Estonia HolidayProvider
     /// </summary>
-    internal class EstoniaHolidayProvider : IHolidayProvider
+    internal sealed class EstoniaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/FaroeIslandsHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// Faroe Islands HolidayProvider
     /// </summary>
     /// <remarks>Adaptation of DenmarkProvider</remarks>
-    internal class FaroeIslandsHolidayProvider : IHolidayProvider
+    internal sealed class FaroeIslandsHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/FinlandHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Finland HolidayProvider
     /// </summary>
-    internal class FinlandHolidayProvider : IHolidayProvider
+    internal sealed class FinlandHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/FranceHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// France HolidayProvider
     /// </summary>
-    internal class FranceHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class FranceHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GabonHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Gabon HolidayProvider
     /// </summary>
-    internal class GabonHolidayProvider : IHolidayProvider
+    internal sealed class GabonHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GambiaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Gambia HolidayProvider
     /// </summary>
-    internal class GambiaHolidayProvider : IHolidayProvider
+    internal sealed class GambiaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GermanyHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Germany HolidayProvider
     /// </summary>
-    internal class GermanyHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
+    internal sealed class GermanyHolidayProvider : IHolidayProvider, ISubdivisionCodesProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GibraltarHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Gibraltar HolidayProvider
     /// </summary>
-    internal class GibraltarHolidayProvider : IHolidayProvider
+    internal sealed class GibraltarHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GreeceHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Greece HolidayProvider
     /// </summary>
-    internal class GreeceHolidayProvider : IHolidayProvider
+    internal sealed class GreeceHolidayProvider : IHolidayProvider
     {
         private readonly IOrthodoxProvider _orthodoxProvider;
 

src/Nager.Date/HolidayProviders/GreenlandHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Greenland HolidayProvider
     /// </summary>
-    internal class GreenlandHolidayProvider : IHolidayProvider
+    internal sealed class GreenlandHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GrenadaHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Grenada HolidayProvider
     /// </summary>
-    internal class GrenadaHolidayProvider : IHolidayProvider
+    internal sealed class GrenadaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GuatemalaHolidayProvider.cs

@@ -9,7 +9,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Guatemala HolidayProvider
     /// </summary>
-    internal class GuatemalaHolidayProvider : IHolidayProvider
+    internal sealed class GuatemalaHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;
 

src/Nager.Date/HolidayProviders/GuernseyHolidayProvider.cs

@@ -10,7 +10,7 @@ namespace Nager.Date.HolidayProviders
     /// <summary>
     /// Guernsey HolidayProvider
     /// </summary>
-    internal class GuernseyHolidayProvider : IHolidayProvider
+    internal sealed class GuernseyHolidayProvider : IHolidayProvider
     {
         private readonly ICatholicProvider _catholicProvider;